1. Field of the Invention
This invention pertains to the field of electronic locking devices and, in particular, to switch operated electronic locks responsive to predetermined digital codes including means to change the codes simply and means to incorporate a multi-station capability. The lock of this invention is responsive to a predetermined but changeable code stored in a shift register, which code is generated by the manipulation of normally open contacts.
2. Description of the Prior Art
Electronic locking devices are well known in the prior patent art and many such devices are commercially available. Representative of the various types of prior art electronic locks are U.S. Pat. Nos. 3,978,376; 3,845,362; 3,953,769; and 3,831,065.
The prior art devices are effective but most have one or more of the following problems. Many such devices use cards or keys, either of which may be forgotten, lost or stolen, resulting in problems ranging from inconvenience to a breach of security. Many of such prior art devices use multiple switches or push buttons, resulting in a multiplicity of wires to the receiver, a higher than necessary cost and difficult installation. Many prior art devices lack versatility in that they are limited in their use due to size, cost or intrinsic design. Many prior art devices are simply too expensive for the average consumer.
The principal object of this invention is to provide an electronic lock which is extremely simple in design, inexpensive to manufacture, simple to install and use, and has a wide diversity of applications. Further objects of this invention are to provide an electronic lock in which keying is done by an easily installable spring return, center-off switch or a pair of push buttons; to provide a simple electronic lock which can be operated from more than one station; to provide both momentary and continuous modes of operation, the continuous mode being disabled by operating the key switch once; to provide an electronic lock in which the combination code and the mode of operation are settable and resettable by both the installer and/or the customer; and to provide a device which may be used in buildings and vehicles.